The present invention relates to silicon photonic devices and methods. More particularly, the present invention provides improved fiber couplers and methods for coupling fiber to silicon waveguide with enhanced coupling efficiency.
Over the last few decades, the use of communication networks exploded. In the early days Internet, popular applications were limited to emails, bulletin board, and mostly informational and text-based web page surfing, and the amount of data transferred was usually relatively small. Today, Internet and mobile applications demand a huge amount of bandwidth for transferring photo, video, music, and other multimedia files. For example, a social network like Facebook processes more than 500 TB of data daily. With such high demands on data and data transfer, existing data communication systems need to be improved to address these needs.
Over the past, the conventional fiber coupling has >3 dB loss in optical power from fiber into a buried silicon waveguide due to poor mode coupling from bigger fiber mode to small waveguide mode. Therefore, fiber couplers with improved and index grading methods, regardless of suspended type or partially supported type, for coupling optical signal from fiber to silicon waveguide are desired.